The structure and properties of nanocomposites based on organosoluble polyimide (PI) and branched functional metallosiloxane oligomers with different types of central metal atoms (Al, Cr, Fe, Zr, Hf and Nb) were investigated. Under the same weight content of the filler, the geometric parameters of the nanoparticles and thermal properties of the nanocomposites did not exhibit a direct relationship with the ability of the materials to withstand the incident flow of oxygen plasma. The atomic oxygenerosion resistance of the filled PI films was influenced by the composition of the hybrid fillerand the type of metal atom in the hybrid filler in the base metallosiloxane oligomer. To determine the effectiveness of the nanoparticles as protective elements of the polymer surface, the nanocomposite erosion yields pertaining to the concentration of the crosslinked organo–inorganic polymer forming the dispersed phase were determined and expressed in mmol per gram PI. The filler concentration in the polymer, expressed in these units, allows for comparison of the efficiency of different nanosize fillers for use in fabricating space survivable coatings. This can be important in the pursuit of new precursors, fillers for fabricating space survivable polymer composites.

In order to expand the range of materials that can be used in outer space and in development of small spacecraft, ladder polyphenylsilsesquioxanes with different molar weights and the Nb-siloxane composites based on them were studied. The properties of the polymer films were studied, including tests in an oxygen plasma flow. Both initial and filled ladder polymers feature extremely low erosion coefficients in the region of 10^–26 cm³/atom O at a high fluence of atomic oxygen of 1.0 × 10²¹ atom O/cm². Ladder polyphenylsilsesquioxane films irradiated with atomic oxygen (AO) retain their integrity, do not crack, and exhibit good optical properties, in particular, a high transmittance. The latter slightly decreases during AO exposure. The Nb-siloxane filling retains the AO resistance and slight decrease in optical transmission due to diffuse scattering on the formed Nb-[(SiO)_x] nanoparticles. Ladder polyphenylsilsesquioxanes demonstrate their suitability for creating protective, optically transparent coatings for small spacecraft that are resistant to the erosive effects of incoming oxygen plasma.

Amorphous polyaryleneetherketone tetrakis(phenyldiethoxysiloxy)hafnium or tetrakis(methyldiethoxysiloxy) hafnium are used as precursors of disperse phase of composites. One of the factors determining the morphology of filled polymer films and the size and shape of particles forming in polymer in situ is the activity of alkoxy groups of metal alkoxysiloxane precursor in hydrolysis and condensation reactions. When using tetrakis(phenyldiethoxysiloxy)hafnium instead of tetrakis(methyldiethoxysiloxy)hafnium, nanocomposites obtained via the sol-gel method are characterized by a uniform distribution of spherical particles of disperse phase.

The morphology and physical properties of nanocomposites based on organosoluble polyimides with different chemical structures are studied. Metalloalkoxysiloxanes that differ in terms of the type of the central metal atom and substituent at the silicon atom, namely, tris(3-aminopropyldiethoxysiloxy)chromium, tris(methyldiethoxysiloxy)gallium, and tetrakis(methyldiethoxysiloxy)titanium, are used as precursors of the dispersed phase. It is shown that the difference in the chemical structure of the matrix polymer, provided that the same precursor of the dispersed phase of the nanocomposite is used, manifests itself in a change in the shape and sizes of the nanoparticles formed in the polymer. Filled polyimide films are characterized by a high resistance to atomic oxygen. The values of the erosion coefficients of the nanocomposites based on them when using tetrakis(methyldiethoxysiloxy)titanium are 89% lower when compared to unfilled polyimides. The ability of the filled polymer films to withstand the erosive action of an incoming oxygen plasma is to a greater extent determined by nanoparticles of the dispersed phase. The protective function of nanoparticles increases with an increase in the number of Si–O–Si blocks in their structure which, in turn, is predetermined by the valence of the central metal atom of the precursor. Thus, polyimides with particles based on tetrakis(methyldiethoxysiloxy)titanium are less susceptible to erosion under the action of atomic oxygen when compared to nanocomposites, the dispersed phase of which is formed based on tris(3-aminopropyldiethoxysiloxy)chromium and tris(methyldiethoxysiloxy)gallium. The chemical structure of the matrix polymer has little effect on the values of the erosion coefficients of the filled polyimide films.